Air chuck



March 9, 1954 p LL 2,671,666

AIR CHUCK Filed May 17, 1952 2 Sheets-Sheet l IN V EN TOR.

PETER P-G HALL P. P-G. HALL March 9, 1954 AIR CHUCK 2 Sheets-Sheet 2 Filed May 17. 1952 H/5 HTTO A/E IIIIIIII PETER P'G. HAL L Patented Mar. 9, 1954 UNITED STATES PATENT OFFICE AIR CHUCK Peter P-G. Hall, Philadelphia, Pa., .assignor to The Hall Planetary Company, Philadelphia, Pa., a corporation of Pennsylvania Application May 17, 1952, Serial No. 288,423

4 Claims. 1

My invention relates to air pressured chucks and is particularly useful on milling machines of the general type disclosed in United States Letters Patent granted to me as follows: 1,316,718, September 23, 1919; 2,008,757, July 23, 1935: but may be used wherever a piece of work must be held for threading or milling or otherwise machining the interior or exterior of a cylinder and the like.

It is an object of my invention to provide a chuck which is simple to operate and can be adapted to engage securely odd shaped pieces of work.

It is a further object of my invention to provide a chuck which can engage a piece of work at two points.

It is a further object of my invention to utilize fluid pressure to energize the holding elements.

It is still a further object of my invention to provide a chuck which promptly releases the work as soon as the fluid pressure has been removed.

It is a still further object of my invention to utilize but one pressure chamber to energize a plurality of holding means.

The principles and characteristic features of my invention and the manner of making and constructing and using my improved air chuck will further appear in the accompanying drawings and the following description explaining the best modes in which I have contemplated using such principles.

Fig. 1 is a side elevational view of my chuck in cross section attached to a miller head, with the chuck piston under pressure;

Fig. 2 is a fragmentary, side elevational view of my chuck, similar to Fig. 1, with the pressure removed from said piston;

Fig. 3 is a front elevational view of my chuck partly broken away taken along the line 3-3 of Fig. 1;

Fig. 4 is a rear elevational view of my chuck taken along the line 4--4 of Fig. 1;

Fig. 5 is a side elevational view of a modification of my chuck which has means for gripping the work piece at two points; and,

Fig. 6 is a side elevational view of a modification of my chuck, in cross section, wherein a diaphragm seals the air pressure chamber.

My improved chuck comprises an annular piston I moveable in an annular cylinder 2 formed in an annular housing 3 which is secured to the face plate 4 and head ring 5 of a miller. The piston I is made as an annular rim on the annular disc 6 which extends beyond the projected limits of the cylinder 2 into a bore 1 within the housing 3 where a rim 8 extends outward from said disc 5 parallel to the piston l to an apertured plate 9 which projects toward the axis of the bore 7 and. housing 3. A collet l0 seats in a collet locating ring I! which is aflixed to the face plate 4 and which projects into the bore 1. When under pressure from the plate 9, the collet moves inwardly along the inclined face l2 of the collet locating ring H toward the axis of the bore 1 and toward the stop 28 seated in the collet locating ring.

Secured to the face I4 of the piston i are a pair of annular gaskets held by a pin or bolt l5. The outer edges l6 and l! of the gaskets engage the walls is and I9 of the cylinder 2 and form a seal for the air chamber 20. Springs 2| recessed in rear face 22 of the disc 6 beneath the piston l engage the face plate 4 and bias the disc 6 and piston l toward the head 23 of the cylinder 2 thereby tending to bias the plate 9 away from the collet Ill. The collet II] is segmented and tends to move toward the plate 9 and away from engagement with the work piece 24. Escape of the collet from the collet locating ring is prevented by the overlap of the apertured plate 9 on the rim 25 of the collet.

Air is supplied to the air chamber 29 by means of a hose 26 which projects through the face of the housing 3.

To operate the chuck, a work piece 24 is moved into the bore 1 over the cutting tool 21 and between the opposing wall faces of the collet until the end of the work piece abuts the work stop 28 secured to the collet locating ring ll inward of the oil seal l3. Air under pressure is then fed through the air hose 26 into the annular air chamber 20. As soon as the air pressure builds up in the air chamber, the piston I compresses the springs 2!. Movement of the piston against the springs brings the plate 9 tightly against the rim 25 of the collet l9 and thereby forces the collet along the inclined face l2 of the collet locating ring I! and down into firm engagement with the work piece 24. As shown in Figs. 1 and 2, the area for holding the work piece is immediately about or adjacent to the point or area in which the cutting tool 27 will engage the inner face of the work piece. Release of the air from the air chamber 29 al lows the springs to bias the piston and plate outwardly thereby permitting the return of the collet and the freeing of the work piece.

Instead of using the two gaskets above noted, I may provide an annular diaphragm 30 extending completely across the annular air chamber as illustrated in Fig. 6. The annular diaphragm is secured along its inner and outer perimeters 3| and 32 by the opposing faces 34 and 35 of the split housing 33. The housing may be held together by suitable means such as bolts 36 and 31'. The inner face 38 of the diaphragm is in engagement with the face I4 of the piston i and any pressure generated in the air chamber 20 is transmitted to the piston and collet as heretofore. The diaphragm is preferably of reenforced rubber composition either natural or synthetic. However, the movement of the piston is so small that the workability of the diaphragm is not dependent on the stretch of the material used but rather on the slight excess of material in the chamber produced by dishing the diaphragm at its interior edges 39 and 49. Use of the diaphragm closed chamber effectively eliminates leakage from the air chamber.

It is sometimes desirable to hold the work piece in more than one area either because of the length of the work piece or because the piece is being worked on at several points. In either case, the provision of an additional point of holding increases the steadiness obtainable and reduces the tendency of a iong work piece to whip. It is particularly important to eliminate the tendency to whip in the work piece where, as here, the thread or finishing operation must be held with in a tolerance of a few thousandths of an inch. I have modified my air chuck, as shown in Fig. 5, to provide for the gripping of the work piece at two points but such gripping is controlled by a single air chamber as heretofore.

In my modified air chuck, illustrated in Fig. 5, the housing secured to the face plate 5-! and centering ring 52 which is, in turn, secured to the head ring 53, forms the side 5 of the annular air chamber 55. The opposite side of the annular air chamber is formed 'by the inner face it of the fiange 5% struck from the larger diameter piston body 51 and, additionally, by the rim *5! 'of the gasket 5-8 secured to the smaller diamet r iston body 59. The rim 6| of the gasket 58 rides on the inner face 63 of the flange 55. The inner end of the air chamber 55 is formed by the piston body 51, its gasket 62 and the gasket retainer 63. The outer end of the air chamber is formed by the piston body 59 and its accompanying gaskets 58 and '34 together with the gasket retainer 74.

Paired springs 65 and 66 are mounted in the piston bodies -51 and 59 and press against the face plate 54 and the forward portion of the housing 53 respectively. These springs bias the piston bodies 57 and 59 toward each other.

Air under pressure enters the chamber 55 through a vestibule M from a hose 58 .by means of inlet passages 3.9 and It. The air passes through the vestibule 6! into the annular chamber 55 through passage ll formed by the opposing faces of the rims l2 and l3 projecting upward from the gasket retainers L3 and B4 respectively. The rims 1-2 and I3 separate the piston bodies 5% and 59 and prevent the flanges on the gaskets 62 and 54 from covering the inlet 18. The touching faces of the rims I2 and 13 are sufficiently rough to allow the passage of air even should the two be meeting so that any air under pressure in the vestibule 6-1 will force itself between the rims and into the air chamber 55 where it will force the two piston bodies 5 and 59 apart.

The Work piece 15 is mounted on a pair of collets l6 and 1! which are seated in the collet locating rings 18 and 19 respectively. As heretofore, the collet locating rings have inclined faces and 8| at their further extremities to guide the collets toward the axis of the housing 50 and into engagement with the work piece 15. Pusher rings 82 and 83 are in engagement with the rear faces of the piston bodies 59 and 51 and in engagement with the collets l6 and H.

In operation, air enters the chamber 55 and forces the piston bodies 51 and 53 against their springs 65 and 63 and against the pusher rings 83 and 82. Pressure on the pusher rings 82 and 83 is directly transmitted to the collets H and 76 which move along the inclined faces SI and 38 into engagement with the work piece 15. It is to be understood that this type of miller does not require that the work piece revolve but on the contrary the cutting tool 84 moves off the center line of the housing 50 and into engagement with the inner face of the work piece 15.

When the air pressure is released, the springs 35 and 65 force the piston bodies back into normal position and the collets It and "(I which are segmented follow the piston bodies in returning to normal position thereby releasing the work piece 75 which then may be extricated from the chuck.

It is to be understood that the movement of the piston bodies 5? and 53 is restricted so that the rim 6! of the gasket 58 never parts from the face fill of the flange 56..

I find that it is sometimes desirable to provide bearing rings 85 and 86 at the rear faces of the piston bodies 57 and 59 in juxtaposition to the pusher rings 82 and '83 in order that no amount of undue Wear shall occur at these points.

Having described my invention, I claim;

1. In combination an annular housing containing a work receiving bore, an inner peripheral lip on said housing adjacent said bore, a chamber in said housing formed by said lip and the peripheral walls of said housing, an expansible collet mounted in said bore adjacent said lip, a rim on said collet projecting toward said lip, an annular ridged plate having a centrally located aperture of a diameter greater than the diameter of said bore, the area adjacent the outer edge of said plate located within and movable axially of said chamber, the inner edge of said plate adjacent said aperture being engageable with said rim on said collet, means for introducing fluid under pressure into said chamber and moving said apertured plate away from the face of said housing and against said collet, and spring means for positioning the outer edge of said plate within said chamber and for moving said plate toward the face of said housing.

2. In combination an annular housing containing a work receiving bore, a lip on said housing, a chamber in said housing having its fixed walls formed by said lip and the peripheral walls of said housing, an expansible collet mounted in said bore in juxtaposition with said lip, a flange on said collet projecdng toward said lip, an apertured plate projecting within and without said chamber, the area of said apertured plate adjacent the outer edge thereof forming a piston movable axially within said chamber, a flange on the inner periphery of said plat engageable with the flange on said expansible collet, and an aperture in said housing for introducing fiuid under pressure into said chamber for moving said apertured plate away from the face of said housing.

3. In combination an annular housing containing a Work receiving bore, a lip on said housing, a chamber in said housing formed by said lip and the peripheral walls of said housing and closed by a flexible end wall, an expansible collet mounted in said bore in juxtaposition with said lip, a flange on said collet projecting toward said lip, an apertured plate projecting within and without said chamber, the area of said apertured plate adjacent the outer edge thereof being in abutting relationship with said flexible wall in said chamber, a flange on the inner periphery of said apertured plate engageable with the flange on said expansible collet, an aperture in said housing for introducing fluid under pressure into said chamber for flexing said flexible wall and for moving said apertured plate away from the face of said housing, and spring means recessed in said apertured plate for biasing said plate toward said flexible wall.

4. A fluid actuated chuck comprising an annular housing enclosing a work receiving bore,

an annular, expandable air chamber within said housing having one side formed by said housing and a pair of interlocking, axially movable pistons forming the other three sides thereof, a collet within each end of said bore for gripping work positioned in said bore, means for introducing fluid under pressure into said chamber between said pistons, operative connections between said pistons and said collets causing the coilets to contract and grip said work upon expansion of said air chamber, and spring means extending between said pistons and said housing for contracting said air chamber and positioning said pistons upon retraction of said fluid under pressure.

PETER P-G. HALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,372,592 Lovely Mar. 27, 1945 2,462,155 Benjamin et al. Feb. 22, 1949 2,509,873 Church May 30, 1950 

